Muusoctopus januarii
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Muusoctopus januarii |
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| ( Hoyle , 1885) |
Muusoctopus januarii is a small to medium-sized cephalopod species from the genus Muusoctopus and at the same time the type species of the genus. He lives in the Atlantic Ocean .
features
anatomy
Muusoctopus januarii reaches a mantle length of 65 millimeters and a total length of 46.5 centimeters. The jacket has a spherical shape with a wide opening. The eyes are relatively large.
The tentacles are very long and slender and reach three to four times the length of the mantle. They are cylindrical in cross-section and of different lengths. The first and second pairs of arms are significantly longer than the other two. The number of uniformly sized suction cups varies between the arms. They are arranged in two rows from the mouth and are moderately spaced from one another. There are 180 suction cups on the longest tentacles. They are small and form several small infundibules .
In male specimens, the third right arm forms the Hectocotylus , which is equipped with 80 suction cups. At the top there is a ligula , the size of which, at eight percent of the hectocotyledon arm, is comparatively small. It has a surrounding, flat, clearly defined edge and a flat inner surface. In the spermatophore groove there are on average 20 weakly developed transverse ribs. The ligula narrows evenly to a pointed point.
The gills have 7 to 8 lamellae per demibranch . The funnel is robust, conically tapered and is located about half-free. The shape of Muller's organ , a glandular tissue in the area of the funnel, has not yet been scientifically described. The radula consists of nine elements, seven rows of teeth and edge plates.
Appearance
In ethanol pickled preparations of Muusoctopus Januarii show a uniformly pink-gray color that is paler at the bottom. Some specimens have 9 rows of short, thin, straight dark lines that are arranged lengthways on the back coat.
habitat
Muusoctopus januarii lives in the coastal waters of the western Atlantic , from the Gulf of Mexico to the central coast of Brazil , at a depth between 350 and 750 meters below sea level.
Reproduction
The females of the Muusoctopus januarii lay relatively large eggs with a capsule length of 14 millimeters.
Systematics
The species was first described in 1885 by William Evans Hoyle as Octopus januarii Steenstrup , MS. on the basis of two specimen copies that were collected as part of the Challenger expedition off the coast of Brazil and off the coast of the Japanese island of Honshu . In 1882, Hoyle was commissioned by John Murray to conduct scientific research on the cephalopod collection of the Challenger expedition. He turned to Japetus Steenstrup for support, who invited Hoyle to come to Copenhagen with the collection in 1884 in order to use the extensive comparative material of the Copenhagen Zoological Museum for his research.
Hoyle saw extensive similarities in the two specimens with some specimens from the museum holdings that had been collected off the coast of Rio (de) Janeiro . For this Steenstrup had apparently already chosen the name Octopus januarii , based on the place of discovery ( Portuguese Janeiro = German January ). Hoyle adopted this name for his specimens and named Steenstrup as the first to describe it. However, since Steenstrup is not known to have published a corresponding publication, Hoyle is officially the first descriptor.
Guy Coburn Robson transferred the species to the genus Benthoctopus newly established by Georg Grimpe in 1921 . Upon a more detailed analysis of the reproductive organs, he also found that the two specimens described by Hoyle could not belong to the same species. The specimen caught in the Atlantic kept its species addition as Benthoctopus januarii , while the specimen collected in the Pacific was assigned to its own species as Benthoctopus profundorum .
In 2002 Bent Jørgen Muus was able to prove that Benthoctopus piscatorum , the type species of the genus Benthoctopus , is identical to Bathypolypus bairdii . The genus Benthoctopus would have become obsolete as a junior synonym of Bathypolypus . In the event that the largely established taxon Benthoctopus should still be retained, Muus suggested redefining the genus and defining Benthoctopus januarii ( Hoyle , 1985) as a new type species. However, Ian G. Gleadall saw no reason to save the polyphyletic collective taxon Benthoctopus in 2004 and placed the proposed type species in its own genus, which he named Muusoctopus in honor of Muus .
Individual evidence
- ↑ a b c d e f P. Jereb, CFE Roper, MD Norman & JK Finn: Cephalopods of the world: An annotated and illustrated catalog of cephalopod species known to date - Volume 3: Octopods and Vampire Squids . FAO Species Catalog for Fishery Purposes, Rome, 2014, ISBN 978-92-5-107989-8 , pp. 151f.
- ^ WE Hoyle: Diagnoses of new species of Cephalopoda collected during the cruise of HMS 'Challenger'. - Part I. The Octopoda. In: Annals and Magazine of Natural History , Series 5, Number 15, 1885, pp. 222-236, ( digitized ).
- ↑ a b c IG Gleadall: Some Old and New Genera of Octopus. In: Interdisciplinary Information Sciences , Volume 10, Number 2, 2004, pp. 99–112, ( digitized version ).
- ^ A b WE Hoyle: Report on the Cephalopoda collected by HMS Challenger during the years 1873-76. - Report on the scientific Results of the Voyage of HMS Challenger during the years 1873-76. In: Zoology , Volume 16, 1886, pp. 1-245, ( digitized ).
- ^ GC Robson: A Monograph of the Recent Cephalopoda based on the Collections in the British Museum (Natural History), Part II, The Octopoda (excluding the Octopodinae). The British Museum (Natural History), London, 1932, pp. 235ff, ( digitized version ).
- ^ B. Muus: The Bathypolypus-Benthoctopus problem of the North Atlantic (Octopodidae, Cephalopoda). In: Malacologia , Volume 44, Number 2, 2002, pp. 175-222, ( digitized version ).